1. Field of This Invention
This invention relates to non-refillable or single use valves for pressurized systems.
2. Prior Art
Pressure tanks or other vessels are usually filled under carefully controlled conditions at a charging station and then distributed to various places for use. When empty it is intended that the vessel be returned to the charging center for appropriate reuse or destruction in the case of single use containers. Unfortunately, the attractive economies of refilling containers at points of use or otherwise repressurizing them under less than carefully supervised conditions has resulted, in the less consequential cases, in introduction of impurities or inferiors refills and, in the more consequential cases, to injurious explosions. The reuse of pressure vessels is highly objectionable for many reasons which relate to safety.
The need has long been felt for a valve which would allow normal filling of the pressure vessel under proper conditions, adequate sealing of the pressure vessel during nonuse, selective discharge of the pressure vessel, and effective prevention of improper and unauthorized refilling of the vessel.
U.S. Pat. No. 3,552,432 discloses an antirefillable valve for a pressure container. The valve includes: a housing providing communication between a port and the pressure container for charging and discharging the latter, a handle, including a stem portion, in threaded engagement with the housing; a sping-urged sealing member for closing and opening communication between the port and the container, the sealing member being mounted for mechanical movement by the handle and for hydraulic movement by container pressure against spring bias; and engageable stop means for limiting retrograde handle movement to below that required for mechanical opening of the sealing member.